Tag: firewall

How to whitelist a hostname in CSF firewall
Firewalls usually allow or block IP addresses. If you need to allow a hostname, you need to find the IP address and white list the IP address. If you use dynamic DNS services like noip, dyndns, the IP address of your hostname changes when your internet provider assigns you a new IP address.

ConfigServer Security and Firewall (CSF) supports dynamic DNS. This feature can be used to whitelist normal hostnames too.

To allow a hostname, login to your server using SSH.

Edit file
```
vi /etc/csf/csf.dyndns
```
In this file, you can add your hostname to the whitelist.

In the CSF config file, you need to make the following changes.
```
vi /etc/csf/csf.conf
```
Set value for DYNDNS
```
DYNDNS = "600"
```
This will tell the CSF firewall to check for the IP address of whitelisted hostnames every 10 minutes. You can change this as needed.
```
DYNDNS_IGNORE = "1"
```
By setting the value of DYNDNS_IGNORE to 1, the CSF firewall will never block these IP addresses even if there are failed login attempts or too many connections.

restart lfd
```
systemctl restart lfd
```
Back to CSF Firewall
December 7, 2023

Install CSF firewall on Ubuntu Server

First, install libwww-perl package needed for CSF firewall

apt -y install libwww-perl

Install CSF with

cd /usr/local/src
wget https://download.configserver.com/csf.tgz
tar -xzf csf.tgz
cd csf
sh install.sh

Change following settings in csf.conf file

/bin/sed -i "s/RESTRICT_SYSLOG\s*=.*$/RESTRICT_SYSLOG = \"3\"/g" /etc/csf/csf.conf
/bin/sed -i "s/SYSLOG_CHECK\s*=.*$/SYSLOG_CHECK = \"3600\"/g" /etc/csf/csf.conf
/bin/sed -i "s/TESTING = \"1\"/TESTING = \"0\"/g" /etc/csf/csf.conf

If you need GUI enabled, edit file

vi /etc/csf/csf.conf

Modify following settings

UI = "1"
UI_PORT = "8282"
UI_USER = "username"
UI_PASS = "password"
UI_ALLOW = "0"

March 26, 2022

Whitelisting an IP Address in CSF Firewall
There are 3 ways to whitelist an IP address in ConfigServer Security & Firewall (csf). Whitelisting an IP address will allow the IP address to access all ports on the server including any closed ports. For example, you can block SSH port 22 on the server. Then add your IP address to the whitelist, now you will be able to access SSH from your IP address.

Using WHM

Login to WHM as user root. Then go to WHM > Plugins > ConfigServer Security & Firewall.

On the text box right side of the “Quick Allow” button, enter the IP address you need to whitelist. Then click on the “Quick Allow” button.

The Quick Deny option below can be used to block an IP address from accessing the server.

Quick Ignore allows you to ignore any IP address. This is the same as Quick ALlow. The difference is if you whitelist an IP address using the Quick Allow option and if the IP fails some ModSecurity rules or makes several failed logins, it gets blocked. If you ignored an IP address, it will never get blocked by ModSecurity or lfd.

Using csf command

If you are logged in to SSH or WHM > Terminal, you can run the following command to whitelist an IP address.
```
csf -a IP_ADDR_HERE
```
IP address can be a single IP address or IP range in CIDR format.

To block an IP, use
```
csf -d IP_ADDR_HERE
```
Manually editing csf.allow

To allow an IP or IP range (CIDR format), you can edit the file
```
vi /etc/csf/csf.allow
```
If you need to Ignore an IP address, then add IP to file
```
vi /etc/csf/csf.ignore
```
IPs added to csf.ignore will never get banned due to LDF or ModSecurity failures. Ips in csf.allow can be blocked by ModSecurity or lfd.

Add your IP to the file. Then restart csf firewall.
```
csf -r
```
See csf
July 12, 2021
Firewalld
firewall-cmd is used to manage firewall (iptables). It is used by default on latest version of CentOS, RHEL.
Check firewall status

To see if firewall is running of not use
```
firewall-cmd --state
```
or
```
systemctl status firewalld
```
To disable firewalls
```
systemctl stop firewalld
systemctl disable firewalld
```
Open a port in firewall

To allow HTTP and HTTPS traffic, run
```
firewall-cmd --permanent --zone=public --add-service=http
firewall-cmd --permanent --zone=public --add-service=https
firewall-cmd --permanent --zone=public --add-service=ssh
firewall-cmd --permanent --zone=public --add-port=25/tcp
firewall-cmd --reload
```
Permanent option make the changes permanant. You need to reload firewall after using –permanent. If you want to open a port in current session and make it permanant, run the command with and with out –permanent.

Open a port range in firewall
```
firewall-cmd --zone=public --add-port=22-65535/tcp
```
Close a port in firewall

To close a port, you can use command same as you open with –add replaced with –remove.
```
firewall-cmd --permanent --zone=public --remove-service http
firewall-cmd --permanent --zone=public --remove-port 25/tcp
```
Whitelist an IP address
```
firewall-cmd --zone=trusted --add-source=IP_ADDR_HERE
```
To remove an IP, use
```
firewall-cmd --zone=trusted --remove-source=IP_ADDR_HERE
```
Firewalld Zones

Zone is a collection of rules that can be applied to a specific interface. Some useful commands are
```
firewall-cmd --get-active-zones
firewall-cmd --get-default-zone
firewall-cmd --list-all-zones
firewall-cmd --info-zone=public
```
Zones are stored in /usr/lib/firewalld/zones

Services

Services are pre-made rules for a specific application. Some useful commands are
```
firewall-cmd --get-services
firewall-cmd --info-service SERVICE_NAME_HERE
```
Services are stoed in /usr/lib/firewalld/services/ or /etc/firewalld/services/.

Save run time configuration into permanant
```
firewall-cmd --runtime-to-permanent
```
iptables

See firewall
December 6, 2020
Firewalld list all open ports
To list all open ports in firealld, run
```
firewall-cmd --list-ports
```
You may need to also use
```
[root@oc1 ~]# firewall-cmd --list-services
http https ssh
[root@oc1 ~]# 
```
Example

See firewalld
December 6, 2020

Firewalld list rules

To list rules use command

firewall-cmd --list-all --zone=public

To list all open ports

firewall-cmd --list-ports

Example

[root@centos7 zones]# firewall-cmd --zone=public --add-rich-rule='rule family="ipv4" source address="10.1.1.2/32" port protocol="tcp" port="1-65535" accept'
success
[root@centos7 zones]# firewall-cmd --list-all --zone=public
public (active)
  target: default
  icmp-block-inversion: no
  interfaces: eth0 eth1
  sources: 
  services: dhcpv6-client ssh
  ports: 25/tcp 9090/tcp
  protocols: 
  masquerade: no
  forward-ports: 
  source-ports: 
  icmp-blocks: 
  rich rules: 
        rule family="ipv4" source address="10.1.1.2/32" port port="1-65535" protocol="tcp" accept
[root@centos7 zones]# firewall-cmd --zone=public --remove-rich-rule='rule family="ipv4" source address="10.1.1.2/32" port protocol="tcp" port="1-65535" accept'                                            
success
[root@centos7 zones]# firewall-cmd --list-all --zone=public
public (active)
  target: default
  icmp-block-inversion: no
  interfaces: eth0 eth1
  sources: 
  services: dhcpv6-client ssh
  ports: 25/tcp 9090/tcp
  protocols: 
  masquerade: no
  forward-ports: 
  source-ports: 
  icmp-blocks: 
  rich rules: 

[root@centos7 zones]#

See firewall-cmd

December 5, 2020

Install CSF Firewall

For non cpanel server, install perl modules

yum install -y perl perl-libwww-perl perl-Time-HiRes unzip bind-utils

On Ubuntu

apt-get install libwww-perl

Once we have requirments installed, install csf with

cd /usr/local/src
wget https://download.configserver.com/csf.tgz
tar -xzf csf.tgz
cd csf
sh install.sh

sed -i "s/RESTRICT_SYSLOG = \"0\"/RESTRICT_SYSLOG = \"1\"/g" /etc/csf/csf.conf

See csf

October 15, 2020

Block Country in CSF firewall
CSF firewall can block all traffic from a country or list of countries using the GeoIP database.

To block a country, edit the file
```
/etc/csf/csf.conf
```
Find
```
CC_DENY=""
```
Replace with
```
CC_DENY="2_LETTER_COUNTRY_CODE"
```
Here is an example to block all traffic from China
```
CC_DENY="CN"
```
If you want to block another country, you can add it like
```
CC_DENY="CN,RU"
```
Now restart CSF firewall with
```
csf -r
```
See CSF firewall
August 30, 2020
Disable IP Block Alerts in CSF Firewall
To disable IP block alert in CSF firewall, run
```
sed -i "s/LF_PERMBLOCK_ALERT\s*=.*$/LF_PERMBLOCK_ALERT = \"0\"/g" /etc/csf/csf.conf
```
Restart lfd and csf
```
systemctl restart lfd
csf -r
```
See csf firewall
September 17, 2019
How to Block a Country in CSF firewall
To block all traffic from a country in CSF Firewall edit file /etc/csf/csf.conf
```
vi /etc/csf/csf.conf
```
Find the line
```
CC_DENY = ""
```
In this line, you can add 2 Letter country code. For example to block China and Russia, add
```
CC_DENY = "CN,RU"
```
Now you need to restart firewall with command
```
systemctl restart lfd
csf -r
```
August 14, 2018
firewall
https://opnsense.org
June 18, 2018
Unban an IP from CSF Firewall
To unban an IP from CSF firewall, run
```
csf -dr IP_ADDR
```
Here i have an IP blocked in firewall.
```
[root@server22 ~]# iptables -L -n | grep 13.224.29.193
DROP       all  --  13.224.29.193        0.0.0.0/0           
LOGDROPOUT  all  --  0.0.0.0/0            13.224.29.193       
[root@server22 ~]# 
```
To see if CSF is blocking the IP, run
```
csf -g IP_ADDR
```
Example

This command also give reason for why the IP is blocked.

Lets unban the IP address with command
```
csf -dr IP_ADDR
```
Now IP should not be listed in iptables, verify it with
```
iptables -L -n | grep IP_ADDR
```
csf
April 13, 2018

Tag: firewall

Using WHM

Using csf command

Manually editing csf.allow

Check firewall status

Open a port in firewall

Open a port range in firewall

Close a port in firewall

Whitelist an IP address

Firewalld Zones

Services

Save run time configuration into permanant